WO2000050959A1

WO2000050959A1 - Developing device and electrophotographic device

Info

Publication number: WO2000050959A1
Application number: PCT/JP1999/000909
Authority: WO
Inventors: Toshihiro Yukawa; Tsuneo Mizuno; Kunihiko Sato; Atsushi Tano; Tomoaki Tanaka; Teruki Kishimoto; Tetsu Takahashi
Original assignee: Fujitsu Limited
Priority date: 1999-02-25
Filing date: 1999-02-25
Publication date: 2000-08-31

Abstract

A developing device which develops a latent image on a photosensitive drum using toner comprising a development roller, reset roller, and a toner agitating paddle, all of which are disposed so that a paddle gear disposed on the rotating shaft of the toner agitating paddle is meshed with both a first gear disposed on the rotating shaft of the development roller and a second gear disposed on the rotating shaft of the reset roller. Also a doctor blade is disposed so that a toner thin-layered area to supply toner onto the surface of the development roller is formed in a triangle obtained by connecting the rotating shafts of the development roller, reset roller, and toner agitating paddle.

Description

Specification

【Technical field】

The present invention relates to a developing device and an electrophotographic apparatus used for printing a single image on a paper by an electrophotographic process, and more particularly, to a stable toner supply even when the attitude of a developing device arranged around a photosensitive drum changes. The present invention relates to a developing device and an electrophotographic device capable of developing.

[Background Art]

Conventionally, in an electrophotographic apparatus used for image printing such as a laser printer or a facsimile, the recording paper is transported at a constant speed due to paper transport leakage, and the electronic recording is performed by an electrostatic recording unit arranged in the transport direction of the recording paper. Images are recorded on the record by the photographic process. The electrostatic recording unit forms a latent image corresponding to image dot data by line scanning of the LED array on a rotating photosensitive drum or scanning of a laser beam from a laser diode, and after developing with a toner by a developing device, Is transcribed on the record.

In recent years, electrophotographic apparatuses for recording a single color image have been put into practical use. Fig. 1 shows a conventional color electrophotographic apparatus, in which four colors of yellow (Y), magenta (M), cyan (C), and black (K) are printed on one side of the photosensitive drum 100. Recording units 1 0 2 — 1. 1 0 2-2, 1 0 2-3, 1 0 2 — 4. Around the photoconductor drum 100, a charger 104, an exposure unit 104 using a laser scanning unit or an LED array, a transfer unit 108, a fixing unit 110, a clean double blade 1 1 2 is arranged.

When printing a color image, a different color toner is used for each rotation of the photoconductor drum, and charging, exposure and development, and transfer and fixing are repeated in four rotations. First, a latent image of yellow component (Y) is formed on the photosensitive drum 100 charged by the charger 104 by optical scanning with the exposure device 106, and the yellow toner of the developing device 104-1 is used. After development, transfer unit 10 Transfer to paper 1 and 4 with 8 and fix with fixing device 110. Next, while feeding the paper 114 after returning it to the initial position, a latent image is formed on the photosensitive drum 100 by the exposure unit 106 in the order of magenta (M), cyan (C), and black (K). After developing with toner of each color of 102-2, 102-3, 102-4, transfer to paper 112 by transfer unit 108 and fix by fixing unit 110 The process is repeated for each rotation of the photoreceptor drum 100, and a blank image is printed. For example, as shown in the developing device 102-1, the developing device 102-1 to 102-4 includes a developing roller 116, a reset roller 118, a toner stirring paddle 120, and a doctor blade. The mounting position is determined in the horizontal direction as shown in the figure to ensure the toner supply property.

FIG. 2 shows the toner supply performance with respect to the arrangement of the developing devices. Fig. 2 (A) shows a horizontal arrangement, in which toner is efficiently sent between the developing roller 118 and the reset roller 120 by the toner stirring paddle 122, and the toner layer is stabilized by the doctor blade 122. The development by the formation of is guaranteed. FIG. 2 (B) shows a case where the developing device 102 is set up with the developing roller 118 turned down. The toner is aggregated by its own weight, and the toner supply becomes unstable. FIG. 2 (C) shows a case where the developing device 102 is inverted, and a certain amount of toner remaining beyond the level indicated by the broken line is required. When the toner power decreases, toner supply becomes unstable. FIG. 2 (D) shows a case where the developer roller is set up above the force of the developing roller 118. If the toner force is reduced below the level indicated by the broken line, the toner cannot be supplied. For this reason, in the conventional color electrophotographic apparatus, the developing units 102-1 to 102-4 must be arranged in a horizontal position as shown in Fig. 1, for example, so as not to deteriorate the toner supply property. Instead, the photoconductor drum 100 had to be placed in a partly biased position. In order to take such an arrangement of the developing devices 102-1 to 102-4, it is necessary to increase the power of the photoreceptor drum 100 and the developing devices 102-1 to 100-4. You have to make it smaller. When the photoconductor drum is enlarged, the size of the device becomes larger, and when the developing device is made smaller, the toner capacity is reduced, and the number of sheets that can be printed by one toner exchange is insufficient.

DISCLOSURE OF THE INVENTION

According to the present invention, it is not necessary to increase the size of the photosensitive drum and the size of the developing device. In addition, there is provided a developing device having a high degree of freedom in arrangement for ensuring stable toner supply even when the mounting posture is changed, and an electrophotographic apparatus using the developing device.

The developing device of the present invention includes at least a developing roller, a reset roller, and a toner stirring paddle, and a paddle gear provided on a rotating shaft of the toner stirring paddle, a first gear provided on a rotating shaft of the developing roller, and a reset roller. The developing roller, the reset roller, and the toner stirring paddle roller are arranged in a triangular shape so that the developing roller, the reset roller, and the toner stirring paddle roller are directly or indirectly associated with both of the second gears provided on the rotating shaft. Then, inside the triangle connecting the rotation axis of the development roller, the rotation axis of the reset roller, and the rotation axis of the toner stirring paddle, a toner thinning region for supplying toner to the surface of the development roller is formed. Place the blade.

Due to the arrangement of the developing roller, the reset roller and the toner stirring paddle, the toner is concentrated on a point inside the triangle connecting the rotation axis of the developing roller, the reset roller and the toner stirring paddle. However, since that point is near the thin layer forming portion near the blade, the toner always gathers near the blade, and the toner layer is efficiently formed regardless of the angle at which the developer is arranged. For this reason, the developing device can be arranged at any position around the photosensitive drum while changing the posture. The developing device of the present invention transmits rotation from a motor to a paddle gear of a toner stirring paddle, and arranges an idle gear between the paddle gear and each of the first gear and the second gear to stir the developing roller and the reset roller. It rotates in the same direction as the paddle. The first gear of the developing roller and the second gear of the reset roller are not engaged.

Further, in the developing device of the present invention, the paddle gear of the toner stirring paddle is rotated by a motor, the paddle gear and each of the first gear and the second gear are directly babble with the paddle gear, and the developing roller and the reset roller are stirred by the toner. It may be rotated in the opposite direction to the paddle.

The reset roller and the toner stirring paddle of the developing device are housed in a case, the developing roller is provided in an opening of the case, and the case has a case opening for exposing a part of the roller surface of the developing roller to the outside, At the case opening, an elastic seal using a sheet-shaped insulator or conductor that contacts at least one of the developing roller and the reset roller is provided. Developing unit is positioned so that the case opening faces downward with this elastic seal Even so, toner leakage can be completely eliminated.

The toner stirring paddle used in the developing device of the present invention is an impeller having a plurality of blades, a brush roller, or a sponge roller.

The present invention provides an electrophotographic apparatus in which a plurality of developing devices are arranged around a photoreceptor and an electrostatic latent image sequentially formed on the photoreceptor is sequentially developed by the plurality of developing devices. Each of a plurality of developing devices used in the electronic photographing apparatus includes at least a developing roller, a reset roller, and a toner stirring paddle, and a paddle gear provided on a rotation shaft of the toner stirring paddle is provided on a rotation shaft of the developing roller. The developing roller, the reset roller, and the toner stirring paddle are arranged in a triangle so as to directly or indirectly engage with both the first gear and the second gear provided on the rotating shaft of the reset roller. A doctor blade is arranged inside a triangle connecting the shaft, the rotation axis of the reset roller and the rotation axis of the toner stirring paddle so as to form a toner thinning region for supplying toner to the surface of the developing roller. Further, the developing device transmits rotation of the motor to a paddle gear of the toner stirring paddle to rotate the developing roller and the reset roller, and the reset roller and the toner stirring paddle are housed in a case, and the developing roller is provided in a case opening. In addition, an elastic seal using a sheet-shaped insulator or a conductor that contacts at least one of the developing roller and the reset roller is provided in the case opening.

In such an electrophotographic apparatus, the toner layer is formed efficiently regardless of the angle of the developing device around the photoreceptor drum. It can be placed at any position around the drum, and can be freely placed around the photoreceptor drum while changing the posture without increasing the size of the photoreceptor drum or reducing the size of the developing unit.

The electrophotographic apparatus according to the present invention includes a plurality of developing units that store color toners such as yellow, magenta, cyan, and black, and forms an electrostatic latent image sequentially formed on a photoreceptor with a corresponding color toner. The images are sequentially developed and a blank image is output. This color electrophotographic apparatus has a single pass in which paper is fed once and a multi-pass in which paper is fed multiple times as a power photographic process. The development of the latent image on the photosensitive drum includes multi-developing, in which all the colors are developed with one rotation of the photosensitive drum, and single developing, in which one color is developed with one rotation of the drum. Multi-developing, single-pass electrophotographic equipment, in addition to the photoconductor and multiple developing units, Charger, Exposure Unit The same number of developing units as the developing units and one cleaning unit are provided. One rotation of the photoconductor drum develops with multiple color toners (multi-development) and then collectively transfers to paper. (Single bus). This multi-development, single-pass electrophotographic apparatus realizes high-speed printing that can produce one image per rotation of the photoconductor. Single development, single-pass electrophotographic equipment has a photoreceptor, multiple developing units, a charging unit, an exposing unit, and a cleaning unit, and develops one color with one rotation of the photoreceptor. The photosensitive drum is sequentially rotated by the number of types of color toners, developed with a plurality of color toners, and then a single color image is transferred to paper at once.

A single-pass, multi-pass electrophotographic apparatus has a charging unit, an exposure unit, and a cleaning unit in addition to the photoconductor and multiple developing units, and develops one color with one rotation of the photoconductor drum. The photosensitive drum is rotated by the number of types of color toner, and is sequentially transferred to the paper every rotation while developing with a plurality of color toners.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a developing device arrangement structure in a conventional apparatus;

FIG. 2 is an explanatory view of a toner supply property with respect to a change in the arrangement posture of a conventional developing device; FIG. 3 is an explanatory view of an electrophotographic apparatus of the present invention in which a single pass is performed by multi-development; FIG. And an explanatory view of a paddle arrangement structure;

FIG. 5 is an explanatory view of a drive gear that determines the arrangement of the rollers and the battle of the developing device of FIG. 4; FIG. 6 is an explanatory diagram of a toner supply operation in the developing device of FIG.

FIG. 7 is an explanatory diagram showing the toner supply operation in the developing device of FIG. 4 at the toner particle level. FIG. 8 is an explanatory diagram of toner supply with respect to a change in the arrangement posture of the developing device of the present invention; FIG. Explanatory drawing of another embodiment of the drive gear that determines the arrangement of the rollers and the battle of the developing device;

FIG. 10 is an explanatory view of the electrophotographic apparatus of the present invention in which a single pass is performed by multi-developing or a multi-pass is performed by single developing;

FIG. 11 is an explanatory view of another embodiment of a toner stirring paddle used in the present invention; FIG. 3 is an explanatory diagram showing an embodiment of the electrophotographic apparatus according to the present invention. The electrophotographic apparatus shown in Fig. 3 employs a multi-developing, single-paste type electrophotographic process.

In this electrophotographic apparatus, a photoreceptor drum 12 is rotatably provided, and four developing units 10-1, 10 and 10 are provided around the photoreceptor drum 12 in correspondence with Y, Μ, C, カラー colors. 2, 10—3, 10—4 are arranged. In front of the developing units 10-1 to 10-4, chargers 14-1, 14-2, 14-3, and 14-4 are respectively arranged. For example, a corona charger and a scorotron charger are used. You. Exposure LED arrays 16-1, 16-2, 16-3, 16-4 which operate as exposure units are arranged inside the photosensitive drums 12 corresponding to the developing units 10_1 to 10-4. The photosensitive drum 12 is fed from a paper tray 18 with paper 20 by paper supply rollers (not shown). At the position where the paper 20 passes, a transfer device 22 force is provided. The rollers that have passed through the transfer unit 22 are sent to a fixing unit 24, where heat fixing is performed by, for example, a heat roller. At a position in the circumferential direction of the photoconductor drum 12 following the transfer device 22, a static elimination brush 26 is provided, followed by a cleaning blade 28.

In the electrophotographic apparatus shown in FIG. 3, while the paper 20 is fed by one rotation of the photosensitive drum 12, the color components Y, M, C, and K are continuously generated by the developing units 10-1 to L0-4. The formation of a latent image and the development with each color toner are sequentially performed, and the image is fixed after being collectively transferred to the paper 20. That is, the photosensitive drum 12 is driven to rotate clockwise during the printing operation. Along with the rotation of the photosensitive drum 12, the rotating surface of the photosensitive drum 12 is charged with a uniform charge by a charger 14-1 provided in front of the developing device 10-1 corresponding to the Υ component. You. Subsequently, the exposure LED array 10-1 emits light by the light emission drive based on the Y component image data, and writes the Y component electrostatic latent image. The Y component electrostatic latent image written on the photosensitive drum 12 is electrostatically developed as a charged toner image by the Y component toner of the developing device 10-1. Such charging, exposure, and development are performed at the following positions of the M component developer 10-2, the C component developer 10-3, and the K component developer 10-4. This operation is performed sequentially to obtain a charged toner image power by superimposing toner images of four colors of Y component, M component, C component and K component. At the timing when the charged toner image force transfer device 22 obtained by superimposing the four color toner images arrives at the position of the transfer device 22, the transfer force of the paper 20 is performed, and Y, M, C, K The electrostatic transfer force of the charged toner image due to the superposition of the four color toner images is collectively performed to form a full color image on paper 20. The paper 20 on which the full-color image transfer has been performed is sent to the fixing unit 24, and the full-color image is thermally fixed to the paper 20. Residual toner that has not been transferred to the paper 20 remains on the surface of the photosensitive drum 12 after the electrophotographic process. This residual toner is removed by the cleaning blade 28 after the charge is removed by the charge removing brush 26.

FIG. 4 shows one of the four developing devices 10-1 to L0-4 provided in the electrophotographic apparatus of FIG. The developing device 10 has a developing roller 32 disposed in an opening of a case 30 and a reset roller 34 and a toner stirring paddle 36 disposed inside the case. The developing roller 32, the reset roller 34, and the toner stirring pad 36 are driven by a gear mechanism disposed on the outer side surface of the case 30, as shown in FIG.

The gear shown in FIG. 5 is provided with a first gear 50 on the rotating shaft 52 of the developing roller 32, a second gear 56 on the rotating shaft 54 of the reset roller 34, and further agitating the toner. A paddle gear 60 is provided on a rotation shaft 58 of the paddle 36. The paddle gear 60 is driven to rotate clockwise in response to rotation from a drive mode (not shown). The first gear 50 of the developing roller 32 and the second gear 56 of the reset roller 34 mesh with the paddle gear 60 via the idle gears 51 and 57, respectively. By the clockwise rotation of 0, the first gear 50 and the second gear 56 are rotated in the same counterclockwise direction. Therefore, the developing roller 32, the reset roller 34, and the inter-toner paddle 36 in FIG. 4 rotate in the same direction.

In FIG. 4, the reset roller 34 is in force contact with the developing roller 32, and the toner agitating paddle 36 is disposed at a position inside the case 30 of the developing roller 32 and the reset roller 34. Have been. If the rotation center of the developing roller 32 is P, the rotation center of the reset roller 34 is Q, and the rotation center of the toner stirring paddle 36 is R, a triangular PQR force connecting the three rotation centers is formed. You. The shape of this triangle PQR is the same as the first gear 50 of the developing roller 32 that engages with the paddle gear 60 shown in FIG. 5 independently. It is uniquely determined by the second gear 56 of the set roller 34.

Here, assuming that the number of teeth of the first gear 50 of the developing roller 32 is Zl, the number of teeth of the second gear 56 of the reset roller 34 is Z2, and the number of teeth of the paddle gear 60 is Z3,

Z 1 = Z2

Z 3> Z 2

Becomes For example, Z 1 = Z 2 = 50 and Z 3 = 100. Here, the idle gears 51 and 57 are provided to change the rotation direction. If the number of teeth is Z4 and Z5, respectively, Z4 = Z5, and the number of teeth can be arbitrarily determined.

Thus, when the number of teeth Z1 of the first gear 50 and the number of teeth Z2 of the second gear 56 are equal, the triangle PQR shown in FIG. 4 forms an isosceles triangle with the line segment PQ as the base. The ratio of the number of teeth Z1 of the first gear 50 of the developing roller 32 to the number of teeth Z2 of the second gear 56 of the reset roller 34 (Z1 / Z2) is allowed to be a maximum of 1.3. That is, the number of teeth Z1 of the second gear 56 of the reset roller 34 is equal to the number of teeth Z1 of the first gear 50 of the developing opening roller 32, or the number of teeth is small within a range up to a maximum of 1,3. Can be. Looking at this relationship with respect to the peripheral speeds of the developing roller 32 and the reset roller 34, assuming that the radii Rl and R2 of the two are equal, the reset roller 34 has the same peripheral speed or a range of up to a maximum gear ratio of 1.3. The peripheral speed of the developing roller 32 is lower than that of the developing roller 32.

Here, the radius of the first gear 50 of the developing roller 32 plus the radius of the idle gear 51 or 52 is Rl, the radius of the second gear 56 of the reset roller 34 is R2, and the radius of the paddle gear 60 is R2. R 3

R 1 = R2

R3> R1

Becomes For example, assume that R1 = R2 = 14 mm and R3 = 2 Omm. Further, the first gear 50, the second gear 56, the paddle gear 60, and the idle gears 51 and 57 may be spur gears or helical gear / integrate gears.

In the positional relationship between the developing roller 32, the reset roller 34, and the toner stirring paddle 36 determined by such gear arrangement, the contact portion of the doctor blade 40 near the center of gravity G of the triangular PQR connecting the respective rotation centers Position this center of gravity G A toner thin film forming region for supplying a toner layer to the surface of the developing roller 32 is present in the vicinity. Here, the developing roller 32 and the reset roller 34 are rotating in the same direction, and the toner supplied by the toner stirring paddle 36 is concentrated near the center of gravity G inside the triangle PQR. Since the point where the toner force is concentrated is located near the toner thin layer forming section which comes into contact with the developing roller 32 with a strong doctor blade 40, even if the remaining toner power is less, the developing device 10 Even at such an angle, the toner can be collected at a point near the center of gravity G of the triangle PQR to the end, and the toner layer can be formed stably and efficiently. The reason why the toner layer can be formed efficiently and efficiently even when the toner remaining amount is small and the arrangement angle of the developing device is different will be geometrically described.

Fig. 6 (A) shows the developing roller 32 and the reset roller for the doctor blade 40.

In this arrangement, a branch-shaped doctor blade 40 in contact with the developing roller 32 forms a toner layer on the surface of the developing roller 32 with its tip. The toner group 62 before forming a layer is stably present near the tip of the doctor blade 40 in the developing machine 10 of the present invention. The toner group 62 before the formation of the layer receives the rotating force and the gravitational force simultaneously from the developing roller 32, the reset roller 34, and the toner stirring paddle 36.

FIG. 6B shows the details of the rotation acting force applied to the toner group 62 before the layer is formed. The acting force applied to the toner group 62 is the force of the vector 64 by the developing roller 32, the force of the vector 66 by the reset roller 34, and the vector 68 by the toner stirring paddle 36. Power. The triangles connected by the vectors 64, 66, 68 form point-symmetric and similar triangles with the triangle PQR determined by the center of rotation. Here, it is assumed that the toner conveying force due to the surface friction between the developing roller 32 and the reset roller 34 is the same, and at that time, the rotation center of the developing roller 32, the reset roller 34 and the toner stirring paddle 36 is used. Assuming that the connected triangles are PQR force isosceles triangles, the acting force of the vectors 64, 66, 68 acting on the toner is also an isosceles triangle. In this way, if the toner is located within the triangle PQR connected by the rotation center of the developing roller 32, the reset roller 34, and the toner stirring paddle 36, the position of the toner group 62 before forming the layer, the developing roller 32, The toner conveyance force received from the reset roller 34 and the toner stirring paddle 36 There are points 7 2 as shown in Fig. 6 (C) where the resultant force is zero. Gravity 70 is applied to the point 72 where the resultant force is zero, but the toner is hardly affected by the gravity 70 due to the resultant force of the toner conveying force. As a result, the effect of gravity 70 can be substantially ignored regardless of the arrangement posture of the developing device 10.

FIG. 7 shows the toner movement in the toner group 62 before the layer is formed in FIG. 6 (A) at the toner particle level. FIG. 7A shows the movement of toner particles in the toner filling area 76 supplied by the toner stirring paddle 36 between the developing roller 32 and the reset roller 34. In the toner filling area 76, the toner particles located on the side of the toner stirring pad 36 move in the direction indicated by the velocity vector 78. Further, the toner particles located on the reset roller 34 side move as indicated by the velocity vector 80. Further, due to the toner conveying force of the developing roller 32, the toner passing between the doctor blade 40 and the toner blade 40 moves as a velocity vector 82. Due to the speed vectors 78, 80, 82 applied by the toner conveying force of the toner stirring paddle 36, the reset roller 34, and the developing roller 32, the immovable toner 8 4 hardly moving in the toner. Can be estimated.

Fig. 7 (B) shows the velocity vector applied to the toner around the immobile toner 84, and the velocity vector 78-1, 8 by the toner stirring paddle 36, the reset roller 34, and the developing roller 32. 0—1, 8 4—1 force is generated. As a result, as shown in FIG. 7C, a movement of the toner toward the formation of the toner layer in the clockwise direction around the immobile toner 84 occurs, so that the immobilized toner 72 also forms the toner layer. Move. The movement of the toner generated by the toner conveying force of the three surrounding rollers overcomes the gravity of the toner, and as a result, the toner layer can be efficiently formed regardless of the position of the developing device. can do.

FIG. 8 shows how toner is supplied when the arrangement posture of the developing device 10 of the present invention is changed. FIG. 8A shows a case where the developing roller 32 is opposed to the photosensitive drum from the right horizontal direction as in the developing device 10-4 in FIG. FIG. 8 (B) shows the case where the whole is rotated 90 ° counterclockwise with respect to FIG. 8 (A), and the photosensitive drum 1 2 near the developing units 10-2 and 10-3 in FIG. In this state, the developing roller 32 is opposed from above. Fig. 8 (C) shows the position further rotated 90 ° counterclockwise with respect to Fig. 8 (B). Of the developing device 10-1. Further, FIG. 8 (D) shows the position rotated 90 °, and in the case of the photosensitive drum 12 in FIG. 3 as an example, when the transfer unit 22 is located at the lower side where the transfer unit 22 is arranged. It is.

In any of the developing devices 10 shown in FIGS. 8A to 8D whose positions are changed by 90 °, the rotation center of the developing roller 32, the reset roller 34, and the toner stirring paddle 36 is determined. Inside the connected triangle, there is the position of the toner group before forming the layer where the toner conveyance force of the point triangle is similar and the toner conveyance force of the similar triangle vector acts, and the effect of the gravity is due to the resultant force of the three force vectors. Since the toner is not received even at the position, the toner layer can be efficiently formed on the developing roller 32 regardless of the attitude of the developing device.

FIG. 9 shows another embodiment of the gear mechanism provided in the developing device 10 of the present invention. In the embodiment of FIG. 5, the developing roller 32, the reset roller 34, and the toner stirring pad 36 are used. In order to make the rotation direction the same, idle gears 51 and 52 are provided between the first gear 50 and the second gear 56 with respect to the paddle gear 60, but in the embodiment of FIG. The present invention is characterized in that the first gear 50 and the second gear 56 are directly combined with the idle gear 60 directly except for the idle gears 51 and 52. In this case, the rotation direction of the paddle gear 60 with respect to the rotation direction of the first gear 50 and the second gear 56 is the same as that of the embodiment of FIG. The paddle gear 36 driven by the paddle gear 60 is far from the thin film forming area by the doctor blade 40, and the influence of the toner conveying force by the paddle rotation is relatively low. Even if the posture of 0 is changed, it is possible to form an area where the toner group strength exists before the layer is formed without being affected by gravity, and the degree of freedom of arrangement of the developing device 10 is almost equivalent to the case of the gear configuration of FIG. Powerful.

FIG. 10 shows another embodiment of the electrophotographic apparatus according to the present invention.

① Single and ° electrophotographic process with multi-development

(2) Single-development multi-photography process

Is adopted.

In FIG. 10, four developing units 10-1, 10-2, and 10-3 corresponding to Υ, M, C, and K are provided around the photosensitive drum 12 similarly to the embodiment of FIG. , 1 0— 4 forces are arranged. For these four developing units 10-1 to 10-4, the hand of developing unit 10-1 In front, one charger 14 and one exposure LED 16 are arranged. A transfer unit 22 for transferring a toner image onto paper 20 is disposed below the last developing unit 10-4, and a position of the photosensitive drum 12 passing through the position of the transfer unit 22 is also provided. Has 28 cleaning blades. The developing devices 10-1 to 10-4 used in the embodiment of FIG. 10 use the structure shown in FIG. 4, FIG. 5, or FIG. 10 similarly to the embodiment of FIG.

The operation of the embodiment shown in FIG. 10 by a single development and single-pass electrophotographic process will be described. In this sindal development, the single-photon and electrophotographic processes consist of developing one color of Y, M, C, and K for each rotation of the photoconductor drum 12 and superimposing it. After completion, the full-color charged toner image is transferred onto paper 20 by transfer device 22 at a time, and is thermally fixed by fixing device 24.

In the case of the single-pass and multi-pass electrophotographic process in the embodiment of FIG. 10, the development and transfer of four colors of Y, Μ, C, and K on paper 20 are repeated. That is, after the photoconductor drum 12 is charged by the charger 14, a latent image of the Y component is first formed by the exposure LED array 16, and the latent image of the Y component is developed by the developing device 10-1. At the position where the toner image of the component arrives at the transfer device 22, the paper 20 is fed to transfer the toner image of the Y component. Next, the paper 20 is returned to the initial position, and then the formation, development, and transfer of the M component latent image are similarly performed using the developing device 10-2. The latent image formation, development, and transfer are similarly repeated for the C component by the developing device 10-3 and the K component by the developing device 10-4, whereby the superimposed and transferred full-color image is finally obtained. Is sent to the fixing unit 24 and heat-fixed.

FIG. 11 shows another embodiment of the toner stirring paddle used in the developing device of the present invention. The toner stirring paddle 80 in FIG. 11 (A) is a cross paddle having four blades. FIG. 11 (B) shows a screw-type agitator having a screw formed around a cylindrical body. Further, FIG. 11 (C) uses a sponge roller 84 having a gear-shaped cross section as a stirring paddle.

Note that the above embodiment has been described with reference to an example of an apparatus configuration used for a color electrophotographic process of Y, Μ, C, Κ. The present invention is not limited to this. Applicable as it is to a device that prints a single image by matching. In the above embodiment, the case where a plurality of developing units are arranged is taken as an example, but it goes without saying that the present invention may be applied to a black-and-white printing electrophotographic apparatus. Furthermore, the present invention is not limited by the numerical values shown in the embodiments, and includes appropriate modifications within a range that does not impair the objects and advantages thereof.

[Industrial applicability]

According to the present invention, since the developing device can be relatively freely arranged around the photoconductor drum in a changed posture, when the color photographic process is adopted, for example, each developing device of YMCK is placed around the photoconductor drum. The device can be downsized because the photoconductor drum does not need to be large. In addition, since multiple developing units are arranged, there is no need to reduce the size of the developing units, and a sufficient toner capacity can be secured, so that the number of printed paper sheets per toner replacement can be sufficiently secured, and frequent toner replacement is required. There is no.

Claims

The scope of the claims

1. At least a developing roller, a reset roller, and a toner stirring paddle, and a paddle gear provided on a rotation shaft of the toner stirring paddle is provided on a first gear provided on a rotation shaft of the development roller and a rotation shaft of the reset roller. A developing device, wherein the developing roller, the reset roller, and the toner stirring paddle roller are arranged in a triangular shape so as to directly or indirectly engage with both of the second gears.

2. In the developing device according to claim 1, toner is supplied to the surface of the developing roller inside a triangle connecting the rotating shaft of the developing roller, the rotating shaft of the reset roller, and the rotating shaft of the toner stirring paddle. A developing device characterized in that a doctor blade is arranged so as to form a thinner region of the toner.

3. In the developing device according to claim 1, the paddle gear of the toner stirring paddle is rotated from the motor by ί≤1, and an idle gear is disposed between the paddle gear and each of the first gear and the second gear. The developing roller and the reset roller rotate in the same direction as the toner stirring pad.

4. In the developing device according to claim 1, the rotation from the motor is transmitted to a paddle gear of the toner stirring paddle, and the paddle gear and each of the first gear and the second gear are directly babbling to the paddle gear. Wherein the developing roller and the reset roller are rotated in the opposite direction to the toner stirring paddle.

5. In the developing device according to claim 1, the reset roller and the toner stirring paddle are housed in a case, the developing roller is disposed in an opening of the case, and at least the developing roller or the reset roller is disposed in the case opening. A developing device _c characterized by providing an elastic seal using a sheet-shaped insulator or a conductor in contact with one side;

6. The developing device according to claim 1, wherein the toner stirring paddle has a plurality of blades. A developing device comprising an impeller, a brush roller, or a sponge roller.

7. An electrophotographic apparatus in which developing rollers of a plurality of developing devices are arranged around a photoreceptor so as to face each other, and the electrostatic latent images sequentially formed on the photoreceptor are sequentially developed by the plurality of developing devices. At

The plurality of developing devices include at least a reset roller and a toner stirring paddle in addition to the developing roller,

A paddle gear provided on the rotation shaft of the toner stirring paddle is engaged directly or indirectly with both a first gear provided on the rotation shaft of the developing roller and a second gear provided on the rotation shaft of the reset roller. The developing roller, the reset roller, and the toner agitation. Place the dolt roller in a triangle,

A toner thinning region for supplying toner to the surface of the developing roller is formed inside a triangle connecting the rotation axis of the development port, the rotation axis of the reset port, and the rotation axis of the toner stirring paddle. Place the doctor blade so that

The rotation from the motor is transmitted to the paddle gear of the toner stirring paddle to rotate the developing roller and the reset roller,

Further, the reset roller and the toner stirring paddle are housed in a case, the image roller is disposed in an opening of the case, and a sheet-like sheet that comes into contact with at least one of the developing roller or the reset roller in the case opening. An electrophotographic apparatus characterized in that an elastic seal using an insulator or a conductor is provided.

8. In the electrophotographic apparatus according to claim 7, the toner stored in the plurality of developing units is a color toner such as yellow, magenta, cyan, black, and the like. An electrophotographic apparatus characterized by sequentially developing an electrostatic latent image with a corresponding color toner and outputting a color image.

9. The electrophotographic apparatus according to claim 8, wherein in addition to the photoconductor and the plurality of developing devices, the same number of chargers and exposure devices as the developing devices and one cleaning unit are provided. Develop with multiple colors of toner in one rotation of the drum, then collectively An electrophotographic apparatus characterized in that the image is transferred onto paper.

10. In the electrophotographic apparatus according to claim 7, in addition to the photoreceptor and the plurality of developing units, one charging unit, one exposing unit and one cleaning unit are provided, and one rotation of the photoreceptor drum is performed. Developing one color at a time, sequentially rotating the photosensitive drum by the number of types of color toners, developing with a plurality of color toners, and then transferring a color image to paper at once. Photo equipment.

11. In the electrophotographic apparatus according to claim 7, in addition to the photoreceptor and the plurality of developing devices, a charging device, an exposing device, and a cleaning unit are provided one by one, One color is developed by rotation, and the photosensitive drum is rotated by the number of types of color toner, and is sequentially transferred to a paper every rotation while developing with a plurality of color toners.